NMR phosphorus-31 relaxation times for diastereomeric phosphines and phosphine oxides

Solvent, salt and high pressure effects on the rate and equilibrium constants for the formation of tri‐n‐butylphosphoniumdithiocarboxylate

“…These values are not considered here as reference data, but they were used as criteria for the correctness of the quantitative 31 P NMR measurements. In our experiments T 1 was always less than the delay time, the flip angle was 30° as recommended,17–20 and the use of two different concentrations of phosphobetaine in DE gave similar values for the reaction volume. A separate experiment in which the delay time was varied from 20 to 50 s with a flip angle of 30° was performed in DE solution, and the relation of the integrals remained constant within 1%.…”

“…There are certain experimental restrictions for quantitative measurements of the concentration of P‐containing compounds using 31 P NMR, and they have been discussed in the literature 17–21. The selected conditions were a compromise between the requirements of the high pressure NMR experiment and the quantitative 31 P NMR measurements,17–20 which states that a flip angle of 30° is optimal and the delay time (between rf pulses) must be at least three times larger than the largest T 1 (phosphorus atom spin lattice relaxation time). T 1 was determined with the inversion‐recovery method for the concentrations used in the high pressure experiments.…”

End Group Functionalization of PFpP Macromolecules Via Fp Migration Insertion Reactions

“…The results are illustrated in Figure . 31 P NMR shows peaks at 73.5 ppm (P 1 in Figure a) and at 32.5 ppm (P 2 in Figure a), which can be assigned to coordinated phosphorus and oxidized phosphine end group, respectively . 1 H NMR of the molecules (Figure b) shows that the signal at 4.5 ppm due to Cp for the Fp end group shifted upfield as a result of MIR and merged with the rest of Cp in the main chain (4.3 ppm).…”

Preparation of the Enantiomers of Compounds Containing Chiral Phosphorus Centers

“…An X-ray crystal- lographic structure determination on 31 allowed chemical correlation of all the structures, 30-33 (188). Both NMR studies (204) and conformational studies (205) have also been reported for menthyl-and neomenthylmethylphenylphosphines.…”